Behavior of Prefabricated Concrete Structures Subjected to Earthquakes

Adoption of precast concrete in construction has accelerated from past few years, due to the basic fact, precast concrete construction is faster, has better quality due to casting and curing in controlled conditions and comparatively costs lesser when compared to reinforced concrete construction. The joints in precast concrete structures have to be designed well as the joints are liable for damage when compared to the structural members when subjected to external loads such as earthquake and wind. Due this reason, the performance of precast concrete structures when subjected to earthquakes is still under assessment when compared to the seismic performance of reinforced concrete structures. The present work is a case study, that assesses the stability and response of a multi storey precast concrete structure in terms of displacements, internal forces developed (bending moment, shear force, axial forces and torsion) in the structural members and at joints. The multi storey precast concrete structure in the present study has plan and stiffness irregularities and is subjected to earthquake loads. A finite element structural analysis of the precast concrete structure subjected to earthquake loads is carried out by incorporating all the material properties of the precast concrete and reinforcing steel used in the precast structural members. The displacements and reaction forces developed at the joints are recorded, to assess the stability of the joints that are subjected to earthquake forces. The internal forces in the precast concrete structural members(beams, columns..) developed are also assessed, to check the amount of load transferred from the joints to the structural members such that, the performance of the joints are evaluated in terms of load transfer and load carrying capacities. Since the joints in the precast concrete structure are the main locations of load transfer to the structural members, their efficacy in terms of complete load transfer to the structural members without undergoing any form of deformation is of outmost importance towards the stability of the entire structure. The assessment of damage taken place at the joints is assessed based on the displacements. This study helps engineers to understand the response of precast concrete structures, and the possible damage in terms of storey drifts taking place at the joints that are present in the structure when subjected to earthquake loads to mitigate instability of the entire structure and also identify possible major structural damages taking place in the structure.